Are these cracks a concern? If not can I just replace the seal or do I have to but the whole thing for 200 bucks a side?
Seal carrier for what? Is that a friction surface. Need a bit more info.
It’s behing the brakes....both sides are cracked and one side was leaking at the seal
If it's a friction surface, as it appears to be, polish it up with a scotch bright. It looks like it's part of the brakes. Those are heat checks, nothing to be concerned about. Same as a flywheel, rotor or drum. As long as the bearing cup bore is good and holds a seal tightly you're in business.
Having a hard time finding just the seals. Only able to find the whole thing for 200 a side
Wash everything spotless. You should see a number stamped in it. I can make out part of it in your picture. It looks like a national seal.
Can almost read it from here, wipe it off.
https://www.epsstore.com/index.php/a49796.html CASE Oil seal, 53.4mm ID x 76.09mm OD x 11.94mm THK
Take seal to local parts store they should be able to cross it. And if Case dealer told you that you couldn't get seal separately then they are lying. When you go back together with brake plate be sure and cover stub shaft with something so seal won't roll or get cut.